The “snapping up” doctrine is a critical negative limit on the objective theory of contract. While the existence and content of an agreement are normally judged by the outward manifestation of intent, the “snapping up” exception prevents a party from enforcing a contract when they actually know the offeror has made a material mistake.
The Objective Foundation and the Exception
English law prioritises commercial certainty by adopting an objective standard: an offer accepted in good faith forms a binding contract even if the offeror made a subjective error. This is illustrated in Centrovincial Estates v Merchant Investors, where a landlord mistakenly offered a lower rent and — the tenant being unaware of the error — was held to the objective terms. But the law will not let a party “snatch at a bargain” they know was not intended, having regard to the parties’ subjective intention to prevent exploitation of an obvious blunder.
The Leading Authority: Hartog v Colin & Shields
In Hartog v Colin & Shields (1939), the defendants mistakenly offered hare skins at a price “per pound” instead of the intended “per piece” — about a third of the market value. Because all negotiations had been per-piece and skins were traditionally sold by the piece, the plaintiff “must have realised, and did in fact know” of the mistake, so no binding contract was formed.
Modern Applications
In Chwee Kin Keong v Digilandmall.com (2004), a website error listed laser printers at S$66 instead of S$3,854. The “streetwise and savvy” buyers could not enforce the “contract”: orders placed in the “dead of night” with “indecent haste” showed they were conscious of an “egregious mistake”.
Actual vs. Constructive Knowledge
A key debate is whether actual knowledge of the mistake is required, or whether constructive knowledge suffices. Recent interpretation (e.g. Longley v PPB Entertainment Ltd, 2022) suggests English law requires actual knowledge; evidence of what a reasonable person ought to have known is merely a tool to infer actual subjective knowledge.
Legal and Policy Significance
The doctrine stops the objective theory becoming a tool for fraud or sharp practice. It creates a one-way escape route: the mistaken offeror can avoid the contract where the mistake was known, but the offeree cannot rely on their own knowledge of the mistake to escape a contract the offeror wishes to uphold — maintaining commercial honesty without undermining the reliability of outward communications.